1. Field of Invention
This invention relates to processing systems utilizing motion picture film handling cartridges, and more particularly to a system for controlling development processing conditions under which a thin coating of processing fluid is applied to an exposed strip of motion picture film while it is being advanced through a processing station within a cartridge. Still more particularly, the invention relates to improvements in the construction of devices for controlling the rate of travel of the film strip across the processing station in accordance with the processing temperature to effect an optimum processing of the film strip with uniformity along the length of the film strip.
2. Description of Prior Art
The field of amateur motion picture photography has developed rapid processing and projection systems utilizing compact multi-purpose film handling cartridges. The film handling cartridge is adapted to be mounted first in a motion picture camera for exposure purposes and then in a motion picture projector for projection purposes. After a strip of film contained in the cartridge has been exposed, the film strip is processed with the cartridge remaining unremoved from the same camera employing a rapid processing system, or mounted in a specially designed processor, or in a processor-projector unit which is constructed to facilitate processing and subsequent projection operations. In these systems, the processing fluid is stored in an applicator within the cartridge from which it is expressed onto the exposed film strip when the processing station is rendered operable. Examplary of such system are those described in U.S. Pat. Nos. 3,641,896; 3,641,909 and 3,687,051.
In applying a thin coating of processing fluid to an exposed strip of motion picture film contained in the cartridge, it is of importance to maintain the temperature of the processing fluid within an optimum processing temperature range during the processing operation, or otherwise satisfactory processing results cannot be effected, particularly when the exposed film is processed not in a processing laboratory, but by the rapid processing system employed in a motion picture camera or projector which is subject to ambient temperature variation. The generally accepted development processing temperature is in a range from about 10.degree. to about 35.degree. C. At the processing laboratory, the processing temperature control can be readily effected with sufficient accuracy by provision of a temperature control device in the processing unit. However, the presently proposed processor-camera units and processor-projector units lack any temperature control device, so that the temperature of the processing fluid is permitted to frequently deviate from the optimum range with variation of the ambient temperature of the unit, and, in the case of the processor-projector unit, by the generation of heat in the illumination system for image projection. It is to be noted that the development process is influenced by the processing time and temperature, these two processing condition control factors being intimately related to each other for effecting an equivalent development result. As the processing temperature increases, the processing time should be decreased to effect equivalent development results. Whilst the technique for controlling the processing time by maintaining a constant rate of travel of an exposed strip of film across the processing station is disclosed, as for example, in U.S. Pat. Nos. 3,616,740 and 3,623,417, no rapid processing system taking into acount the temperature effect on the development process have so far been available.